0023-6152

AA00697606

1911227

In this study, 150 liquid fertilizers in 2012 and 70 liquid fertilizers in 2015 were sampled and analyzed to derive the process monitoring factors for the production of stabilized liquid fertilizer during the liquid composting of pig slurry. Dissolved oxygen (DO) and oxidation–reduction potential (ORP), which are major operating factors of the liquid composting process, tend to increase with the improvement of organic stabilization degree in the liquid composting of pig slurry, but pH and suspended solid (SS) did not show any significant difference regardless of the organic stabilization degree of liquid fertilizer. Electric conductivity (EC), soluble chemical oxygen demand (SCODCr), total nitrogen (TN), and ammonium nitrogen (NH4+–N) showed a significant decreasing tendency, and nitrate nitrogen (NO3 – –N) and total phosphorus (TP) showed no significant differences with the improvement of organic stabilization degree in the liquid composting of pig slurry. And there was a significant correlation between the EC, TN, and NH4 +–N parameters in the correlation analysis of the chemical properties of the stabilized liquid fertilizer. Therefore, EC, SCODCr, TN, and NH4+–N were derived as chemical parameters that could distinguish the characteristics of stabilized liquid fertilizer. Especially, the EC parameter was evaluated as an useful indicator for the quality control of liquid fertilizer in the monitoring of overall liquid composting process of the pig slurry.